How Bluetooth and 802.11 will team up to deliver high speed wireless connections

Bluetooth technology has helped make this possible, and the Bluetooth profiles that enable sharing of entertainment data are well-established. But usage of these profiles and implementation of hardware and software support for these use cases are currently hindered by the perception that the data transfer speed Bluetooth technology currently offers is insufficient for these scenarios.

For example, while Bluetooth technology can easily handle the transfer of a single file, consumers would like the flexibility to share more than just one photo or one song, instead sharing the whole album or a vacation's worth of pictures and video.

The Bluetooth SIG and manufacturers have devised a solution already inside a growing number of portable devices: the 802.11 radio built into portable devices for Wireless LAN connectivity.

With Bluetooth and 802.11 radios already sitting next to each other in so many mobile device—not to mention PC—a solution is ready with an established radio technology that boasts global regulatory approval and a data rate more than adequate for sharing all kinds of entertainment data.

Generic AMP: Using the best radio for the job
At the heart of Bluetooth high speed technology is the concept of the Generic Alternate MAC/PHY (Generic AMP), an innovative formula for radio substitution that allows the Bluetooth stack to dynamically select the right radio for any job.

The Generic AMP enables Bluetooth profiles and protocols to take advantage of higher data rates using one or more alternate high speed radio technologies. Figure 1 illustrates the generic AMP principle.

Click here for Figure 1.
Figure 1: The generic AMP is a key feature of the Bluetooth SIG's performance roadmap.

The AMP modifies the standard Bluetooth Core architecture to enables multiple alternate radios under the L2CAP layer, with the standard Bluetooth radio (denoted BR/EDR, for Basic Rate or Extended Data Rate of 1 or 3 Mbps, respectively) used for discovery and connection setup and association.

Bluetooth 802.11 AMP supports the ratified 802.11 standards
Bluetooth technology's standards for interoperability require that we select the 802.11 standards that have been fully tested and ratified for inclusion in Bluetooth 802.11 AMP specification.

For this reason, the Bluetooth 802.11 AMP explicitly supports the ratified standards 802.11a, b, and g, all of which are proven and reliable and offer data rates more than adequate for the entertainment-centric use cases manufacturers and customers are demanding now: 24 Mbps as standard and 12 Mbps with a simultaneous SCO connection.

To ensure that all devices using the 802.11 AMP will interoperate, and to guarantee a high data rate across all devices, support for 802.11g is mandatory. Further, the SIG plans to aggressively pursue the inclusion of 802.11n in the 802.11 AMP specification upon ratification of 802.11n by the IEEE.

Bluetooth UWB and 802.11 roadmap
In parallel to the development of the 802.11 AMP, key Bluetooth SIG member companies are hard at work on the Ultra Wideband AMP, which uses the WiMedia UWB radio.

The UWB AMP promises even higher data rates sufficient to stream high-definition video, and it fits in the Bluetooth technology roadmap as the highest-speed Bluetooth physical radio conceived to date.

The 802.11 and UWB AMPs complement each other, with the 802.11 AMP supporting data transfer applications with a radio technology available today, and the UWB AMP supporting high-definition streaming using the radio that will set the standard for short-range connectivity in the years to come.

Seamless and transparent to the consumer
Customers already associate Bluetooth technology with a simple and reliable user experience. Bluetooth security and pairing are already trusted and familiar, and the Bluetooth v2.1 products reaching the market now are setting a new standard for ease of use with innovations such as Simple Pairing that significantly reduce the input needed to securely pair devices.

The same high standard of ease of use applies to Bluetooth high speed technology, whose operation can and must be seamless and transparent to the consumer. Accordingly, the specification calls for no additional user interaction to select high speed data transmission.

The Bluetooth stack will recognize the need for fast transfer of a large amount of data and automatically assign the 802.11 AMP to the task. When the transfer is completed and high speed is no longer required, the 802.11 radio will be shut down, and the standard Bluetooth radio will activate to maintain the Bluetooth connection.

Messaging the consumer
The Bluetooth SIG's development of multiple high speed—as well as ultra low power—radio channels means more alphabet soup for engineers, but the SIG and members agree that none of this additional complexity should reach the end user.

Communicating a product's Bluetooth high speed capability to consumers will be done via the already-established Experience Icons, additions to the regular Bluetooth logo that are already in use by leading Bluetooth manufacturers that denote which use cases a device supports.

The SIG has developed an appropriate high-speed icon for the 802.11 AMP that will make the device's capability clear and unmistakable to the consumer.

Bluetooth 802.11 AMP use cases
Already popular among younger owners of Bluetooth mobile devices who share content with their friends, this use case is currently served by the "Send via Bluetooth" function already implemented on many mobile phones, PCs and PDAs. The scenario's appeal grows with the addition of the 802.11 high speed channel reducing file transfer times by a factor of ten or more.

Along with demand for easier image sharing comes the demand for convenient printing from both digital cameras and camera phones to a personal printer or photo kiosk.

Bluetooth technology currently supports printing photos from most camera phones and a handful of digital cameras, but this capability would see more widespread use if the transfer time were reduced. Feedback from consumer printing manufacturers suggests a consumer expectation of three seconds to transfer an 8 megapixel camera image to a printer or printing kiosk.

This translates to an 8-14 Mbit/sec transfer rate to meet the 3 second requirement—well within the capability of Bluetooth high speed technology using the 802.11 AMP.

The speed of a standard Bluetooth link renders synchronization between mobile devices and PCs relatively slow when images and large files are included. As with the sharing and printing scenarios, the sync scenario gains attractiveness with increased transfer speed.

We are now beginning to see the emergence of wireless-enabled portable music players with Bluetooth technology to stream audio to wireless headphones, while the 802.11 radio itself has made its way into some players as well.

While standard Bluetooth technology is ideal for audio streaming, Bluetooth high speed technology offers a compelling scenario for loading new songs onto a music player. Bluetooth device discovery and pairing are ideal for ad-hoc connections to another music player, a PC, or a store kiosk, and the 802.11 AMP lets users add a new album's worth of music in an acceptable timeframe of 60 seconds or less.

There are good reasons to believe that easy content sharing from portable devices such as music or media players and mobile phones to stationary devices such as PCs, set-top boxes, and TVs can have a very bright future if Bluetooth wireless technology is integrated into home entertainment systems.

For example, consider a mobile phone and set-top box both equipped with Bluetooth high speed technology. Bluetooth technology lets the user select and send video files up to movie length for viewing on-the-go with the portable device, with the 802.11 AMP providing a reasonable transfer time of 5 to 6 minutes or less.